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Publication numberUS5295967 A
Publication typeGrant
Application numberUS 07/949,610
Publication dateMar 22, 1994
Filing dateSep 23, 1992
Priority dateSep 23, 1992
Fee statusPaid
Also published asDE69322044D1, DE69322044T2, EP0589356A2, EP0589356A3, EP0589356B1
Publication number07949610, 949610, US 5295967 A, US 5295967A, US-A-5295967, US5295967 A, US5295967A
InventorsJean-Claude Rondelet, Jean-Michael Dupouy
Original AssigneeBecton, Dickinson And Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Syringe pump having continuous pressure monitoring and display
US 5295967 A
Abstract
A syringe pump is disclosed having a transducer for detecting the force on the syringe pusher. The detected force is translated into a pressure which is continuously displayed so that the user can anticipate the occurrence of an occlusion. The syringe pump also has a device for pre-selecting a range of acceptable pressures.
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Claims(7)
What is claimed is:
1. A syringe pump for pumping fluid from a syringe, the pump comprising:
means for detecting the pressure in the syringe substantially continuously; and
means for displaying the pressure in the syringe substantially continuously such that the pressure in the syringe can be monitored during pumping.
2. The syringe pump of claim 1 wherein the means for detecting the pressure comprises:
means for measuring the force on the plunger of the syringe; and
means for converting the measured force to a pressure.
3. The syringe pump of claim 1 further comprising:
means for selecting an acceptable pressure range in the syringe; and
means for indicating the selected acceptable pressure range.
4. The syringe pump of claim 3 wherein the means for displaying comprise a digital segmented display.
5. The syringe pump of claim 4 wherein the digital segmented display comprises means for displaying the pressure in analog form.
6. The syringe pump of claim 3 wherein the means for displaying comprise a pointer for indicating the pressure in the syringe.
7. The syringe pump of claim 3 wherein the means for indicating the selected acceptable pressure range comprise three regions, a first region for low pressures, a second region for medium pressures and a third region for high pressures.
Description
BACKGROUND FIELD OF THE INVENTION

The invention relates generally to the field of syringe pumps. In particular, the invention relates to a syringe pump having a continuous pressure monitoring and display device.

BACKGROUND

A syringe pump is a device for pumping fluid from a syringe into a patient. The syringe is placed in the pump and connected to the patient via an infusion line. During the course of infusing medication into a patient, it is possible for an occlusion to arise in the infusion line. Such a condition, if undetected may cause injury to the patient.

An occlusion in the infusion line will cause the pressure in the syringe to increase. This in turn will cause the force between the pusher of the syringe pump and the syringe plunger to increase. Syringe pumps exist in the prior art in which the force between the pusher of the syringe pump and the syringe plunger or the pressure in the syringe are monitored. In prior art pumps, when the force between the pusher and the plunger or the pressure in the syringe increased above a predetermined threshold, an alarm was generated. This alarm was essentially a binary alarm. That is to say, it was either "on" or "off." Therefore, the user of the syringe pump would not know whether the pressure in the syringe was building up to an unacceptable level. The user would only know when the alarm limit was reached. Thus, remedial action could only be taken once the user was aware of the occlusion. The binary nature of the alarm therefore prevented preemptive action from being taken to remove the occlusion prior to the alarm limit being reached.

SUMMARY OF THE INVENTION

The invention is a syringe pump in which the pushing force on the syringe plunger is continuously measured and displayed so that the user can monitor the development of occlusions in the infusion line. The invention is made up of a syringe pump having a housing on which a syringe is mounted. The syringe plunger is pushed by means of a motor driven pusher. A transducer is provided to measure the force on the pusher. The force on the pusher is translated into a pressure and the pressure is displayed on a pressure display.

The syringe pump may also include means for selecting ranges of occlusion pressures so that the user may monitor the pressure inside the syringe and insure that it remains within the pre-selected range. The invention also displays the actual pressure in the syringe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a syringe pump embodying the invention;

FIG. 2 is a perspective view of the drive mechanism of the syringe pump;

FIG. 3 is a cross sectional view of the pusher mechanism of the invention;

FIG. 4 is a perspective view of the pusher disc and force transducer;

FIG. 5 is a block diagram of the main components of the invention;

FIG. 6a-f are schematic diagrams of the electronics of the invention; and

FIG. 7 is a diagram showing the segments of the pressure display.

DETAILED DESCRIPTION OF THE DRAWINGS

A syringe pump 8 embodying the invention is shown in FIG. 1. Housing 10 supports syringe 12, pusher 14 and syringe clamp 16. Syringe clamp 16 holds syringe 12 in place on housing 10. Plunger 18 of syringe 12 is pushed by pusher 14 which is driven by an electric motor via a lead screw (see FIG. 2).

Pusher 14 is provided with antisiphon catch 20 which engages flange 18a of plunger 18, thus preventing plunger 18 from moving independently of pusher 14. Pusher 14 is also provided with pressure plate 22 for pushing directly against flange 18a thereby pumping fluid from syringe 12.

FIG. 2 shows the chassis and mechanical components of pump 8. Chassis 226 carries motor 230 and lead screw 222. Motor 230 drives lead screw 222 via gear assembly 232. Pusher 14 is driven by the interaction of pusher block 228 with lead screw 222. Pusher block contains half nuts 322, 324 which interact with lead screw 222 (see FIG. 3).

FIG. 5 is a block diagram showing the main electronic components of the invention. Transducers are provided to detect various parameters of the syringe pump which are displayed on panel 24. The transducers are: force transducer 36, antisiphon catch detector 38, disengage detector 40 and syringe clamp detector 42. The outputs of these transducers 60, 62, 64 and 66 respectively are fed into central processing unit 44 via various signal processing modules. Schematic diagrams of the various electronics modules are shown in FIGS. 8a. The values and types of the components are indicated on the schematic diagrams.

Central processing unit 44 comprises microprocessor 46 (FIG. 6a) with random access memory 53 (FIG. 8a), watchdog 48 (FIG. 6b), EPROM 50 (FIG. 6a) and EEPROM 52 (FIG. 6c). Watchdog 48 monitors microprocessor 46 to ensure its proper operation. EEPROM 52 contains data concerning the parameters of the syringes used in the pump. EPROM 50 contains a software program which controls the operation of the syringe pump.

The output of force transducer 36 is conditioned by signal conditioning circuit 54 (FIG. 6d), which converts the output of force transducer 36 into a form suitable for input into analog to digital converter 56 (FIG. 6e). Analog to digital converter 56 digitizes the analog output and produces serial output 58 which is in turn fed into input port 60 of microprocessor 46.

FIGS. 4 shows force transducer 36 in greater detail. Force transducer 36 is made up of four strain gauges in a wheatstone bridge configuration. The bridge has an impedance of 350 ohms or 1 Kohm with a tolerance of +/-15%. The range of force measurements is 0 to 150N. The bridge sensitivity is 1.7 mV/V to 2.4 mv/V under a load of 150N at 20 degrees centigrade. The bridge is powered intermittently under the control of microprocessor 46 (line CDANA in FIGS. 6a and 6d) in order to conserve energy.

As seen in FIGS. 3 and 4, strain gauges 112 are glued onto beam 114. When force is applied to pressure plate 22, beam 114 flexes, causing strain gauges 112 to distort and produce output 60.

Output 60 of force transducer 36 is fed into conditioning module 54 (FIG. 6d) and thereafter into analog to digital converter 56 which converts the conditioned output of force detector 36 into serial output 58. Serial output 58 is then fed into input 60 of microprocessor 46.

Resident in EPROM 50 is a software program for microprocessor 46 which calculates the pressure inside syringe 12 continuously as the force on the plunger 18 is measured by force transducer 36. Certain parameters which are used by the program to calculate the pressure in the syringe and stored in EPROM 52. Since syringe pump 8 is programmable to accommodate various types of syringe, a set of parameters for each type of syringe, is stored in EPROM 52.

The parameters stored in EEPROM 52 include:

Ff=average frictional force between the syringe plunger and the syringe barrel at null (atmospheric) pressure.

PC=the pressure in the syringe when a calibration force is applied to the plunger. The calibration force is typically 5 kgF and leads to a value of Pc of around 0.7 bar, a usual pressure threshold.

Fc=the force with which the plunger is loaded to obtain a pressure of Pc in the syringe.

The program in EPROM 50 is used by microprocessor 46 to calculate the pressure in the syringe. Microprocessor 46 then compares the calculated pressure with a pressure value or values stored in EEPROM 52 for that syringe. If the calculated pressure exceeds the stored pressure, an occlusion alarm is generated by microprocessor 46.

The algorithm for calculating the pressure in the syringe is: ##EQU1## where F is the force measured by force transducer 36 and Fc, Ff and Pc are the parameters defined above.

The main advantages of this formula over the traditional formula described in the BACKGROUND section above are (1) it is not highly dependent on the frictional force in the syringe which is known to vary with pressure and (2) that the cross-sectional area of the syringe need not be determined. Rather, the pressure in the syringe is calculated using parameters which are easy to determine empirically.

Thus it can be seen that the error in the pressure measurement using the present invention is substantially reduced in comparison to that of the prior art.

Pressure display 27 is supplied with data from microprocessor 46. Microprocessor 46 calculates the pressure in syringe 12 and outputs the calculated pressure to display 27 via a serial data bus 29 (SI in FIGS. 6a and 6f). Display 27 (See FIG. 7) is a liquid crystal display made up of three segments 27a, 27b and 27c. Segments 27a, 27b and 27c correspond to low, medium and high pressure ranges which may be pre-selected by the user using switch 35 on panel 24 (FIG. 1). Switch 35 is linked to microprocessor 46 which communicates the selection of segments 27a, 27b or 27c via serial bus 29. Display 27 also includes pointer 28 which indicates the measured pressure to the user.

Pointer 28 is made up of segments 27a-j each of which corresponds to a measured pressure. LCD driver (IC6 in FIG. 8f) actuates segments 27a, 27b or 27c depending on the pressure range selected by the user. The LCD driver also actuates the segment in 27a-j which corresponds to the pressure data provided by microprocessor 46. Thus, the user is provided with a digital display providing information as to (1) whether the pressure in the syringe is approaching a pre-set occlusion pressure and (2) what the actual pressure in the syringe is. The number of segments results in an analog form despite the fact that it is implemented by means of a digital segmented display. This allows the user to take remedial action well before an occlusion becomes a problem. It also permits more accurate use of the syringe pump.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2742901 *Jan 15, 1952Apr 24, 1956Sigfrid KrauthamerApparatus for injection of fluid under controlled pressure conditions
US4624658 *Nov 5, 1984Nov 25, 1986Intermedicat GmbhDistensible syringe and sensor for injectors
US4741732 *May 9, 1985May 3, 1988The University Of MelbourneOpen-loop control of drug infusion
US4767406 *Oct 10, 1986Aug 30, 1988Vickers Plc.Syringe pumps
US4902277 *Aug 26, 1987Feb 20, 1990OrthoconceptCirculating a liquid through a joint
US4950246 *Apr 27, 1988Aug 21, 1990Spruyt-Hillen B.V.Injection pen
US4952205 *Oct 27, 1989Aug 28, 1990B. Braun Melsungen AgPressure infusion device
US5034004 *Jun 20, 1988Jul 23, 1991The University Of MelbourneInfusion pump and drive systems therefor
US5087245 *Mar 13, 1989Feb 11, 1992Ivac CorporationSystem and method for detecting abnormalities in intravascular infusion
US5140862 *Feb 6, 1991Aug 25, 1992Pappalardo Joseph TInjection pump calibration device
Non-Patent Citations
Reference
1 *Lymphography Injector, c. 1972 Cat. No. 404 100, Copy in 604/155, Gp. 330.
2Lymphography Injector, c. 1972 Cat. No. 404-100, Copy in 604/155, Gp. 330.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5425716 *Aug 10, 1992Jun 20, 1995Atom Kabushiki KaishaInfusion apparatus
US5533981 *Oct 6, 1994Jul 9, 1996Baxter International Inc.Syringe infusion pump having a syringe plunger sensor
US5545140 *Jul 5, 1994Aug 13, 1996Ivac CorporationSyringe plunger driver
US5772635 *May 15, 1995Jun 30, 1998Alaris Medical Systems, Inc.For infusing medical fluid to a patient
US5808203 *May 12, 1997Sep 15, 1998Medrad, Inc.Fluid pressure measurement devices
US5814015 *Feb 24, 1995Sep 29, 1998Harvard Clinical Technology, Inc.Infusion pump for at least one syringe
US5817075 *Feb 28, 1995Oct 6, 1998Photogenesis, Inc.Method for preparation and transplantation of planar implants and surgical instrument therefor
US5868728 *Feb 28, 1995Feb 9, 1999Photogenesis, Inc.Medical linear actuator for surgical delivery, manipulation, and extraction
US5954527 *Aug 29, 1996Sep 21, 1999Fresenius AgModular system, particularly for biomedical applications, a unit and a communication system for use therein
US6036678 *Jan 15, 1998Mar 14, 2000Photogenesis, Inc.Method for preparation and transplantation of planar implants and surgical instrument therefor
US6113574 *Jul 27, 1998Sep 5, 2000Spinello; Ronald P.Anesthetic injection apparatus and methods
US6200289 *Nov 30, 1998Mar 13, 2001Milestone Scientific, Inc.Pressure/force computer controlled drug delivery system and the like
US6482186Sep 29, 2000Nov 19, 2002Sterling Medivations, Inc.Reusable medication delivery device
US6497680Dec 17, 1999Dec 24, 2002Abbott LaboratoriesMethod for compensating for pressure differences across valves in cassette type IV pump
US6743202Jun 22, 2001Jun 1, 2004Medrad, Inc.Encoding of syringe information
US6786885 *Jan 22, 2001Sep 7, 2004Milestone Scientific IncPressure/force computer controlled drug delivery system with exit pressure control
US6866648 *May 28, 2002Mar 15, 2005Macosta Medical U.S.A., L.L.C.Method and apparatus to decrease the risk of intraneuronal injection during administration of nerve block anesthesia
US6872197Nov 16, 1998Mar 29, 2005Schering AgTank for administering flowable substances
US6887216 *Jan 22, 2001May 3, 2005Milestone Scientific, Inc.Pressure/force computer controlled drug delivery system with automated charging
US6932242 *Jun 20, 2003Aug 23, 2005B. Braun Melsungen AgSyringe pump
US6942636Oct 29, 2002Sep 13, 2005Hospira, Inc.Method for compensating for pressure differences across valves in cassette type IV pump
US6945954Jan 22, 2001Sep 20, 2005Milestone Scientific, Inc.Drug delivery system with profiles
US7294312 *Feb 20, 2003Nov 13, 2007Medtronic, Inc.that make more accurate and reduces risk of filling reaction chambers of cartridge cells with samples to conduct coagulation tests employing the plunger technique
US7311879Aug 14, 2003Dec 25, 2007Hodson Steve Jhaving plungers movable along barrel, detectors and control circuits, used for for the controlled addition of chemical reagent to chemical reaction mixtures
US7402154Jun 21, 2005Jul 22, 2008Hospira, Inc.Method for compensating for pressure differences across valves in cassette type IV pump
US7407489Jun 21, 2005Aug 5, 2008Hospira, Inc.Methods for compensating for pressure differences across valves in IV pumps
US7449008 *Apr 20, 2004Nov 11, 2008Milestone Scientific, Inc.Drug infusion device with tissue identification using pressure sensing
US7455663Dec 26, 2006Nov 25, 2008Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US7500959 *Oct 4, 2001Mar 10, 2009Novo Nordisk A/SMedication delivery system with improved dose accuracy
US7517332Apr 13, 2005Apr 14, 2009Gambro Lundia AbInfusion device for medical fluids
US7569050Aug 23, 2005Aug 4, 2009Medtronic Minimed, Inc.Infusion device and method with drive device in infusion device and method with drive device in separable durable housing portion
US7625354Nov 11, 2005Dec 1, 2009Milestone Scientific, Inc.Handpiece for fluid administration apparatus
US7641649Aug 23, 2005Jan 5, 2010Medtronic Minimed, Inc.Reservoir support and method for infusion device
US7682338Dec 26, 2006Mar 23, 2010Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US7686787Aug 23, 2005Mar 30, 2010Medtronic Minimed, Inc.Infusion device and method with disposable portion
US7699833Aug 23, 2005Apr 20, 2010Moberg Sheldon BPump assembly and method for infusion device
US7727224Oct 13, 2008Jun 1, 2010Macosta Medical U.S.A.,L.L.C.Method and Apparatus to Decrease the risk of intraneuronal injection during administration of nerve block anesthesia
US7736338Dec 26, 2006Jun 15, 2010Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US7736344Nov 22, 2006Jun 15, 2010Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US7744589Jun 7, 2007Jun 29, 2010Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US7789857Dec 26, 2006Sep 7, 2010Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US7794434Nov 20, 2006Sep 14, 2010Medtronic Minimed, Inc.Systems and methods allowing for reservoir filling and infusion medium delivery
US7811262Nov 20, 2006Oct 12, 2010Medtronic Minimed, Inc.Systems and methods allowing for reservoir filling and infusion medium delivery
US7828764Nov 20, 2006Nov 9, 2010Medtronic Minimed, Inc.Systems and methods allowing for reservoir filling and infusion medium delivery
US7905868Oct 27, 2006Mar 15, 2011Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US7922689Jun 20, 2002Apr 12, 2011Timotheus Joan Marie LechnerDevice and method for locating anatomical cavity in a body
US7935085Jan 28, 2010May 3, 2011Medtronic Minimed, Inc.Infusion device and method with disposable portion
US7955057 *Jun 22, 2005Jun 7, 2011Erbe Elektromedizin GmbhMedical pump
US7955305Aug 23, 2005Jun 7, 2011Medtronic Minimed, Inc.Needle inserter and method for infusion device
US7959715Apr 29, 2008Jun 14, 2011Medtronic Minimed, Inc.Systems and methods allowing for reservoir air bubble management
US7963954Apr 22, 2008Jun 21, 2011Medtronic Minimed, Inc.Automated filling systems and methods
US8025658Mar 25, 2009Sep 27, 2011Medtronic Minimed, Inc.Adhesive patch systems and methods
US8083716Dec 26, 2007Dec 27, 2011Medtronic Minimed, Inc.Systems and methods allowing for reservoir air bubble management
US8137314Oct 27, 2006Mar 20, 2012Medtronic Minimed, Inc.Infusion medium delivery device and method with compressible or curved reservoir or conduit
US8172804Jul 11, 2008May 8, 2012Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US8172929May 27, 2011May 8, 2012Medtronic Minimed, Inc.Systems and methods allowing for reservoir air bubble management
US8187228Nov 30, 2006May 29, 2012Medtronic Minimed, Inc.Infusion pumps and methods and delivery devices and methods with same
US8202250Nov 30, 2006Jun 19, 2012Medtronic Minimed, Inc.Infusion pumps and methods and delivery devices and methods with same
US8226615Nov 24, 2008Jul 24, 2012Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US8277415Nov 22, 2006Oct 2, 2012Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US8303574Feb 27, 2009Nov 6, 2012Deka Products Limited PartnershipAdhesive and peripheral systems and methods for medical devices
US8323250Feb 7, 2008Dec 4, 2012Medtronic Minimed, Inc.Adhesive patch systems and methods
US8333938 *May 23, 2007Dec 18, 2012Medronic, Inc.Test cartridge holder for blood samples
US8378837Feb 18, 2010Feb 19, 2013Hospira, Inc.Occlusion detection system
US8434528Apr 29, 2008May 7, 2013Medtronic Minimed, Inc.Systems and methods for reservoir filling
US8444607Oct 8, 2008May 21, 2013Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US8475432Sep 3, 2010Jul 2, 2013Medtronic Minimed, Inc.Infusion medium delivery system, device and method with needle inserter and needle inserter device and method
US8512288Sep 1, 2006Aug 20, 2013Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US8529553Jul 2, 2009Sep 10, 2013Medtronic Minimed, Inc.Infusion medium delivery device and method with drive device for driving plunger in reservoir
US8597243Apr 8, 2008Dec 3, 2013Medtronic Minimed, Inc.Systems and methods allowing for reservoir air bubble management
US8597270Jun 17, 2011Dec 3, 2013Medtronic Minimed, Inc.Automated filling systems and methods
US8613725Apr 8, 2011Dec 24, 2013Medtronic Minimed, Inc.Reservoir systems and methods
US20120195793 *Jan 30, 2012Aug 2, 2012Fresenius Medical Care Deutschland GmbhClamp mounting for a syringe of a dosing apparatus, dosing apparatus and blood treatment apparatus
WO1999025308A1Nov 16, 1998May 27, 1999Schering AgTank for administering flowable substances
WO1999052575A1 *Mar 5, 1999Oct 21, 1999Mark HochmanPressure/force computer controlled drug delivery system and the like
WO2003101526A1 *May 9, 2003Dec 11, 2003Sergio GiglioliMethod and appratus to decrease the risk of intraneuronal injection during administration of nerve block anesthesia
WO2007055697A1 *Nov 11, 2005May 18, 2007Mark HochmanHandpiece for fluid administration apparatus
WO2013075622A1 *Nov 21, 2012May 30, 2013Zensun (Shanghai) Science & Technology LimitedSyringe pump and drive system thereof
Classifications
U.S. Classification604/154, 604/67, 128/DIG.12
International ClassificationA61M5/168, A61M5/145, A61M5/20, A61M5/00
Cooperative ClassificationY10S128/12, A61M5/1456, A61M5/16854
European ClassificationA61M5/168D4
Legal Events
DateCodeEventDescription
Aug 26, 2005FPAYFee payment
Year of fee payment: 12
Aug 30, 2001FPAYFee payment
Year of fee payment: 8
Nov 12, 1997ASAssignment
Owner name: FRESENIUS AG, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BECTON DICKINSON AND COMPANY;REEL/FRAME:008800/0001
Effective date: 19971106
Sep 8, 1997FPAYFee payment
Year of fee payment: 4
Nov 19, 1996ASAssignment
Owner name: FRESENIUS AG, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BECTON DICKINSON AND COMPANY;REEL/FRAME:008231/0326
Effective date: 19961028
Nov 29, 1993ASAssignment
Owner name: BECTON, DICKINSON AND COMPANY, NEW JERSEY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:RONDELET, JEAN-CLAUDE;DUPOUY, JEAN-MICHEL;REEL/FRAME:006779/0539
Effective date: 19931110